This invention relates to magnetic materials useful in electrical apparatus such as transformers, and more particularly to amorphous magnetic alloys and to a configuration which reduces losses during their operation.
There has been considerable interest in the use of transition metal based amorphous alloys as possible magnetic core materials (e.g. for transformers). These alloys, which are typically produced by rapidly cooling a jet of liquid metal against the surface of a rapidly rotating cylinder, exhibit no magnetocrystalline anisotropy. Generally electrical resistivities are two-three times higher than in traditional Fe-Si or Ni-Fe magnetic alloy systems and low coercivities and core losses are exhibited in the as-cast state. In addition, the magnetic properties can be further improved by a stress relief anneal and also by cooling in the presence of an applied magnetic field. Despite the low coercivities and high resistivities, the losses (although very good) have in the past been generally inferior to the commercially available 4-79 Permalloy.
A variety of commercially available amorphous magnetic alloys are available (for example, "Metaglas", Registered Trademark Allied Chemical Corp.). The type referred to herein as 2605A has a Fe.sub.78 Mo.sub.2 B.sub.20 composition and a relatively high saturation. The type referred to herein as 2826 (see U.S. Pat. No. 4,144,058) has a Fe.sub.40 Ni.sub.40 P.sub.14 B.sub.6 composition and a somewhat lower saturation. The type referred to herein as 2826MB is an amorphous magnetic alloy related to the 2826 and has a Fe.sub.40 Ni.sub.38 Mo.sub.4 B.sub.18 composition.